"I don't know Catherine Zeta-Jones personally but what she has decided to do it SO brave," Lovato Tweeted Thursday. "And SO difficult but worth it... I'm proud of her."

Lovato, 18, who has been open about her own personal struggles, entered a treatment facility last fall for what she now calls "a nervous breakdown."

"I was really bad off," she told Seventeen magazine, which she has joined as a contributing editor. "My parents and my manager pulled me aside and said, 'You need to get some help.' It was an intervention. I wanted freedom from the inner demons. I wanted to start my life over."